Is there any mod that allows you to hide a board from administrators as well? Two of the forum admins on a forum (including me) shouldn't be able to view a certain board because we two are just web admins and should not view the content inside a certain board.
Not by default since in SMF world and admin can see all things.
What it may work is to create a separate group, give this group admin privileges and setup the hidden boards so only the "real" admin group can see that board and not the "second" admin group.
that may just work but I dunno, I haven't done anything like that before.